JP2604051Y2 - Excimer lamp discharger - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeless discharge tube apparatus which emits ultraviolet rays by exciting the luminescent material of a non-electrode discharge tube filled with a luminescent material (gas) by microwave irradiation. The present invention relates to an excimer lamp discharge device for discharging an excimer lamp.

[0002]

2. Description of the Related Art Ultraviolet light, particularly ultraviolet light having a wavelength of 200 nm to 350 nm, has a large energy and acts strongly on a substance, and is therefore widely used in the industrial and medical fields. It has already been widely applied to printing, painting, and the like, and has also been used for processing electronic materials such as VLSI and semiconductors. It is also being used as a sterilizing means without residual or accumulated chemicals, and has been adopted in other biological fields and in the chemical industry such as vitamin synthesis.

As an ultraviolet ray generating apparatus, an electrodeless discharge tube apparatus that excites a light emitting material by irradiating a microwave to a discharge tube in which a light emitting material such as mercury is sealed has been used. As the light source, a mercury lamp is used, which uses discharge light emission of mercury vapor, and is classified into low-pressure, high-pressure, and ultra-high-pressure mercury lamps according to the vapor pressure at the time of lighting. Of these, low-pressure mercury lamps are most often used, but output per wavelength is small and only a limited plurality of emission wavelengths can be obtained.

There are various lasers such as excimer lasers as monochromatic light sources capable of selecting a wavelength with a very large output. This excimer laser requires a gain sufficient to exceed the oscillation threshold for laser oscillation because the laser medium itself is absorbed by light.
It is required to excite a laser gas at a high pressure of orr with a high excitation density of several Mw / cm ³ .

[0005] Therefore, in order to excite a discharge of an excimer laser, a sophisticated and complicated excitation technique such as a large current density discharge and a pre-ionization technique is indispensable, and an expensive optical system for an excimer laser resonator is required. . Laser oscillation can be output only with a short pulse width of 100 nsec or less, the maximum average output is about 40 W, and the irradiation area is 27
mm × 10 mm, and could not be a light source for continuous operation. Incidentally, the luminous efficiency is at most about 1%.

For this reason, there has been an industrial need for a simple and strong light source for ultraviolet irradiation capable of selecting a wavelength at an appropriate cost. Excimer lamps are being developed to meet the above-mentioned requirements, and have the feature that they have less radiation light energy than excimer lasers, but have a large irradiation area and can be operated continuously.

[0007] Further, since the excimer lamp has no light emission threshold, the excitation density of input power can be greatly reduced. Excimer lamps have improved luminous efficiency by selecting a low-pressure operation method of gas, which is a lamp medium and a luminescent material. For excimer lamps,
Attempts are being made to increase the excimer generation efficiency by raising the electron temperature by lowering the pressure of the gas that is the lamp medium as compared with the excimer laser. The lower pressure has enabled the use of common low pressure discharge techniques such as conventional mercury lamps.

FIG. 2 schematically shows a conventional excimer lamp discharge device of this type. In this device, a low-pressure discharge device mainly used for emitting light from a mercury lamp is used for excimer lamp discharge. In addition to the lamp house and the blower shown in the figure, a power supply unit (not shown) is used. Consists of three parts. In the figure, 1 is an excimer lamp which is an electrodeless discharge tube, 2 is a microwave resonator forming a microwave cavity, 3 is a dielectric mirror which reflects ultraviolet light emitted by the excimer lamp 1 in a certain direction, 4 is an antenna which is a first microwave coupler, 5 is a magnetron which is a first microwave generator for generating a continuous microwave, 6 is a waveguide, and 7 is a wall of a microwave cavity. The metal mesh 8 is a blower for cooling the lamp house having the above configuration through a through hole (not shown).

With this configuration, continuous microwave power emitted from the magnetron 5 is supplied to the microwave resonator 2 via the waveguide 6 and the antenna 4, and the microwave power is supplied to the excimer laser 2. The light-emitting material (gas) enclosed in the lamp 1 is excited, and is discharged by plasma discharge.
It emits light.

The ultraviolet rays are radiated in all directions, but the dielectric mirror 3 has a parabolic shape and is focused in the direction of the metal mesh 7. The metal mesh 7 is formed of a metal mesh so as to have a cut-off characteristic with respect to microwaves, transmits only emitted light without leaking microwaves in the microwave cavity to the outside, and transmits the ultraviolet light. Release to the outside. By arranging the object in front of the metal mesh, processing such as hardening and sterilization is immediately performed.

The performance of the excimer lamp discharge device will be specifically described. The magnetron 5 has an oscillation frequency fo = 24
Two magnetrons for a 50 MHz microwave oven are used, and a microwave power of up to 1.5 kW can be obtained by this magnetron alone. As shown in FIG. 2, the magnetron 5 is divided into two parts to uniformly discharge the rod-shaped excimer lamp. The size of the excimer lamp is 8 mm × 250 mm in diameter × length, and when microwave power P = 0.75 kW is applied to each magnetron 5, that is, when the microwave power to be applied is 1.5 kW , ,
An excimer lamp having a gas pressure of 50 torr has an irradiation area of 10 mm × 250 mm and a maximum average output of 30 W.

In addition, the microwave power can be improved
In order to supply the lamp, a wave-shaped antenna is used as the microwave coupler. A slit for coupling may be used for simple coupling, but by using this antenna, it becomes easy to selectively excite the vicinity of the excimer lamp, and a strong light output is obtained.

[0013]

In an excimer lamp using such an excimer lamp discharge device, a lamp medium to be filled as a luminescent material is a halogen gas, (CL, Br, I, F) and a rare gas. (Inert gas such as xenon gas, krypton gas, and argon gas) and buffer gas (helium gas, neon gas, and argon gas). By changing the mixing ratio or combination of the lamp media, a lamp giving various center wavelengths from the visible region to the vacuum ultraviolet region can be obtained.

The present inventor performed various experiments by changing the mixing ratio and combination of the lamp media, and measured the light output of the ultraviolet light at that time. FIG. 3 is a characteristic diagram when xenon gas and CL ₂ gas are used as a lamp medium and microwave power is applied. An excimer lamp using xenon gas and CL ₂ gas (hereinafter referred to as “XeCL lamp”) has a microwave power and light output (A) of the XeCL lamp when the total gas pressure is 50 torr.
And the relationship between microwave power and luminous efficiency (B).

As is apparent from FIG. 3, the light output is increased by the input of the microwave power. However, the luminous efficiency is degraded as the input microwave power increases, and it is not sufficient to simply input the microwave power to obtain a stronger light output.

Accordingly, in order to obtain a high light output, a stronger light output can be obtained by optimizing the gas pressure and the composition ratio of the XeCL lamp. When the gas pressure of the lamp was changed in a low pressure range of 100 torr or less, when the gas pressure of the XeCL lamp was 60 torr or more, it was difficult to start excimer discharge using a conventional excimer lamp discharge device, and no ultraviolet light was generated. Was.

The present invention has been made in order to solve the above-mentioned problems, and has an excimer lamp discharge apparatus for exciting an excimer lamp having a high gas pressure and capable of obtaining a strong light output with a simple structure. The purpose is to provide.

[0018]

The present invention achieves the above object.
To emit light at a pressure of 60 torr to 100 torr
A rod-shaped electrodeless discharge tube in which a material is sealed, and the electrodeless discharge tube
A microwave resonator in which the tube is arranged, and a first oscillation frequency
Microwave generation to generate continuous microwaves
A living being and a microphone generated by the first microwave generator
A first microwave for coupling a microwave to the electrodeless discharge tube
A coupler and a microwave having a pulse waveform of a second oscillation frequency
A second microwave generator for generating
The microwave generated by the microwave generator is
Having a second microwave coupler coupled to the tube
It is characterized by the following.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below. The configuration of the present invention is to provide a conventional excimer lamp discharge device with a second microwave generator for generating a pulsed microwave, and a pulsed microwave generated by the second microwave generator. A second microwave coupler coupled to the electrodeless discharge tube is provided.

FIG. 1 shows an outline of an embodiment of the present invention. 2, the same reference numerals as those in FIG. 2 denote the same or corresponding components, and 11 denotes a pulse magnetron which is a second microwave generator for generating a microwave having a pulse waveform.
2 is a waveguide, 13 is a microwave of a pulse waveform generated by the pulse magnetron 11 and an excimer lamp 1.
7 is a coupling slit of the second microwave coupler for coupling to the second microwave coupler.

With such a configuration, the microwave having the pulse waveform generated by the pulse magnetron 11 is supplied to the microwave resonator through the waveguide 12 and the coupling slit 13, and the microwave is supplied to the microwave resonator. The light-emitting material sealed in the excimer lamp 1 is excited by a high discharge voltage by a microwave having a pulse waveform, and operates as an excitation trigger signal.

A magnetron 5 for generating a continuous wave
And a pulse magnetron 11 for generating a pulse wave
Have independent operation modes without interfering with each other at the individual coupling portions and the like because the oscillation frequencies are different. Also, in the experiment relating to the present invention, good characteristics were obtained by coupling using the coupling slot, but it goes without saying that coupling is further improved by coupling using an antenna.

The excimer lamp 1 is excited by a magnetron 5 for generating a continuous wave and a pulse magnetron 11 for generating a pulse wave. The pulse waveform of the pulse magnetron 11 of the excitation trigger signal enables efficient excitation even in an excimer lamp having a high discharge starting voltage. And excimer lamp 1
Since the light emitting material enclosed in the substrate is excited at a higher level, the discharge can be easily started even if the gas pressure is high, and ultraviolet light having a strong light output is generated.

The pulse magnetron 11 used in the experiment of the present invention has an oscillation frequency fo = 3050 MHz, a pulse output Ppeak = 50 kW, and a pulse width tr = 1 μsec.
c, the repetition period ts = 1 msec. FIG. 4 shows the characteristics of the light output at this time. In the figure, the conventional 50t
1.5k microwave power with orr XeCL lamp
The light output at the time of W was 30 W (D). Then, when the microwave power is 1.5 kW using the apparatus of the present invention and a pulse wave having the above specification is added, 75 torr is obtained.
The XeCL lamp of r was easily excited, and the light output at that time was 45 W (C).

By doing so, it was confirmed that an excimer lamp of 60 torr or more, which did not generate ultraviolet light in the conventional apparatus, could be excited. Further, it is apparent that higher light output can be obtained by adjusting the mixed components of the gas, the coupling method, and the like.

[0026]

As described above, the present invention provides a pulse magnetron for generating a pulse wave for discharging an excimer lamp and a gas of 60 torr or more with a simple structure such as providing a coupling slit. Ultraviolet light can be generated even with a pressure excimer lamp.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a conventional excimer lamp discharge device.

FIG. 3 is a characteristic diagram showing a relationship between optical output and microwave power.

FIG. 4 is a characteristic diagram showing the light output of the present invention.

[Description of sign]

 1, excimer lamp 2, microwave resonator 3, dielectric mirror 4, antenna 5, magnetron 6, waveguide 7, metal mesh 8, blower 11, pulse magnetron 12, waveguide 13, coupling slit

Claims (1)

(57) [Scope of request for utility model registration] 1. A rod-shaped electrodeless discharge tube in which a light emitting material is sealed at a pressure of 60 torr to 100 torr, a microwave resonator in which the electrodeless discharge tube is disposed, and a first oscillation circuit.
A first microwave generator for generating a continuous microwave wave number, the first microwave coupler of microwave generated by said first microwave generator causes coupled to the electrodeless discharge tube, a second microwave generator for generating microwave pulse waveform of the second oscillation frequency, a second micro the microwave generated by the microwave generator of the second cause coupled to the electrodeless discharge tube excimer lamp discharge device according to claim <br/> that a wave combiner.